This writing at Got Questions sums up what is a dominant strain in Christian thinking:
The Scriptures that describe God apparently “changing His mind” are human attempts to explain the actions of God. God was going to do something, but instead did something else. To us, that sounds like a change. But to God, who is omniscient and sovereign, it is not a change. God always knew what He was going to do. God also knew what He needed to do to cause humanity to do what He wanted them to do. God threatened Nineveh with destruction, knowing that it would cause Nineveh to repent. God threatened Israel with destruction, knowing that Moses would intercede. God does not regret His decisions, but is saddened by some of what humanity does in response to His decisions. God does not change His mind, but rather acts consistently to His Word in response to our actions.When we take the approach that God does not change His mind, we have developed a theology that prevents us from taking certain passages of Scripture at face value. This theology stems from a specific understanding of the omniscience of God when it comes to the future. A cosmological viewpoint must be held that holds that God exists outside of time and space. In this view, all time-past, present, and future-has already happened. He can just view any point of time and see what happened or, from our perspective, what will someday happen. This cosmological viewpoint is not contained within the Bible, yet is dogmatically held by many. Not being in Scripture does not mean it is automatically wrong, but it also does not make it guaranteed to be right. It is worth further examination.
Thomas Aquinas developed what seems to be the most prevalent view today. In his view, God stands outside time and can know everything that we do as freewill actors. Since He knows what we will do "in advance", he knows our actions before they are even conceived and long after they have occurred. The freewill actor's future actions remain unknown to us and others in linear time with us but are logically necessary to God on account of His infallibly accurate all-encompassing view.
I feel inferior and out of place to disagree with a intellectual giant like Thomas Aquinas, but I do not see the biblical evidence to support that view. Nor do I see biblical situations where having that view would be necessary to understand Scripture. Actually holding the view that God knows everything that will happen creates quite a quandary rather than the security the view hopes to create.
The writer at Got Questions wrote: "God does not change His mind, but rather acts consistently to His Word in response to our actions." It is a nice trick of semantics, but that is not what Scripture says. Scripture explicity states that "God changed His mind".
And the Lord said to Moses, “I have seen this people, and behold, it is a stiff-necked people. Now therefore let me alone, that my wrath may burn hot against them and I may consume them, in order that I may make a great nation of you.” But Moses implored the Lord his God and said, “O Lord, why does your wrath burn hot against your people, whom you have brought out of the land of Egypt with great power and with a mighty hand? Why should the Egyptians say, ‘With evil intent did he bring them out, to kill them in the mountains and to consume them from the face of the earth’? Turn from your burning anger and relent from this disaster against your people. Remember Abraham, Isaac, and Israel, your servants, to whom you swore by your own self, and said to them, ‘I will multiply your offspring as the stars of heaven, and all this land that I have promised I will give to your offspring, and they shall inherit it forever.’ ” And the Lord relented from the disaster that he had spoken of bringing on his people. Then Moses turned and went down from the mountain with the two tablets of the testimony in his hand, tablets that were written on both sides; on the front and on the back they were written. The tablets were the work of God, and the writing was the writing of God, engraved on the tablets. When Joshua heard the noise of the people as they shouted, he said to Moses, “There is a noise of war in the camp.” But he said, “It is not the sound of shouting for victory, or the sound of the cry of defeat, but the sound of singing that I hear.” And as soon as he came near the camp and saw the calf and the dancing, Moses’ anger burned hot, and he threw the tablets out of his hands and broke them at the foot of the mountain. Exodus 32:9-19 (ESV)The New American Standard translates Exodus 32:14 as, "So the LORD changed His mind about the harm which He said He would do to His people." The King James goes even a little further: "And the LORD repented of the evil which he thought to do unto his people."
In this passage in Exodus, we see that Moses prayed and God changed his plan on what He was going to do with the people of Israel. I struggle with what exactly in Moses' speech influenced God to change His mind. I don't think we can say with definite certainty. It was not like Moses told Him something that He did not already know. It appears that God was looking for someone to stand up and worry about His name. Moses' prayer showed His willingness to be the type of man that God desired to use. Moses shared with God an anger toward the actions of the people and a concern for the name of the Lord. Moses rightly explained that God had linked Himself to these people and His name would be linked to their success or their failure.
The book of Jonah shares another story where God changes His mind.
Then the word of the Lord came to Jonah the second time, saying, “Arise, go to Nineveh, that great city, and call out against it the message that I tell you.” So Jonah arose and went to Nineveh, according to the word of the Lord. Now Nineveh was an exceedingly great city, three days’ journey in breadth. Jonah began to go into the city, going a day’s journey. And he called out, “Yet forty days, and Nineveh shall be overthrown!” And the people of Nineveh believed God. They called for a fast and put on sackcloth, from the greatest of them to the least of them.The word reached the king of Nineveh, and he arose from his throne, removed his robe, covered himself with sackcloth, and sat in ashes. And he issued a proclamation and published through Nineveh, “By the decree of the king and his nobles: Let neither man nor beast, herd nor flock, taste anything. Let them not feed or drink water, but let man and beast be covered with sackcloth, and let them call out mightily to God. Let everyone turn from his evil way and from the violence that is in his hands. Who knows? God may turn and relent and turn from his fierce anger, so that we may not perish.” When God saw what they did, how they turned from their evil way, God relented of the disaster that he had said he would do to them, and he did not do it.But it displeased Jonah exceedingly, and he was angry. And he prayed to the Lord and said, “O Lord, is not this what I said when I was yet in my country? That is why I made haste to flee to Tarshish; for I knew that you are a gracious God and merciful, slow to anger and abounding in steadfast love, and relenting from disaster. Therefore now, O Lord, please take my life from me, for it is better for me to die than to live.” And the Lord said, “Do you do well to be angry?” Jonah went out of the city and sat to the east of the city and made a booth for himself there. He sat under it in the shade, till he should see what would become of the city.
Jonah 3:1-4:5 (ESV)
God's course of action was changed because the people changed.
Now we will read the story of God removing the kingship from Saul, the first king of Israel.
The word of the Lord came to Samuel: “I regret that I have made Saul king, for he has turned back from following me and has not performed my commandments.” And Samuel was angry, and he cried to the Lord all night. And Samuel rose early to meet Saul in the morning. And it was told Samuel, “Saul came to Carmel, and behold, he set up a monument for himself and turned and passed on and went down to Gilgal.” And Samuel came to Saul, and Saul said to him, “Blessed be you to the Lord. I have performed the commandment of the Lord.” And Samuel said, “What then is this bleating of the sheep in my ears and the lowing of the oxen that I hear?” Saul said, “They have brought them from the Amalekites, for the people spared the best of the sheep and of the oxen to sacrifice to the Lord your God, and the rest we have devoted to destruction.” Then Samuel said to Saul, “Stop! I will tell you what the Lord said to me this night.” And he said to him, “Speak.” And Samuel said, “Though you are little in your own eyes, are you not the head of the tribes of Israel? The Lord anointed you king over Israel. And the Lord sent you on a mission and said, ‘Go, devote to destruction the sinners, the Amalekites, and fight against them until they are consumed.’ Why then did you not obey the voice of the Lord? Why did you pounce on the spoil and do what was evil in the sight of the Lord?” And Saul said to Samuel, “I have obeyed the voice of the Lord. I have gone on the mission on which the Lord sent me. I have brought Agag the king of Amalek, and I have devoted the Amalekites to destruction. But the people took of the spoil, sheep and oxen, the best of the things devoted to destruction, to sacrifice to the Lord your God in Gilgal.” And Samuel said,The NIV translates 1 Samuel 15:29, "He who is the Glory of Israel does not lie or change his mind; for he is not a man, that he should change his mind."
“Has the Lord as great delight in burnt offerings and sacrifices, as in obeying the voice of the Lord? Behold, to obey is better than sacrifice, and to listen than the fat of rams. For rebellion is as the sin of divination, and presumption is as iniquity and idolatry. Because you have rejected the word of the Lord, he has also rejected you from being king.” Saul said to Samuel, “I have sinned, for I have transgressed the commandment of the Lord and your words, because I feared the people and obeyed their voice. Now therefore, please pardon my sin and return with me that I may worship the Lord.” And Samuel said to Saul, “I will not return with you. For you have rejected the word of the Lord, and the Lord has rejected you from being king over Israel.” As Samuel turned to go away, Saul seized the skirt of his robe, and it tore. And Samuel said to him, “The Lord has torn the kingdom of Israel from you this day and has given it to a neighbor of yours, who is better than you. And also the Glory of Israel will not lie or have regret, for he is not a man, that he should have regret.” Then he said, “I have sinned; yet honor me now before the elders of my people and before Israel, and return with me, that I may bow before the Lord your God.” So Samuel turned back after Saul, and Saul bowed before the Lord. Then Samuel said, “Bring here to me Agag the king of the Amalekites.” And Agag came to him cheerfully. Agag said, “Surely the bitterness of death is past.” And Samuel said, “As your sword has made women childless, so shall your mother be childless among women.” And Samuel hacked Agag to pieces before the Lord in Gilgal. Then Samuel went to Ramah, and Saul went up to his house in Gibeah of Saul. And Samuel did not see Saul again until the day of his death, but Samuel grieved over Saul. And the Lord regretted that he had made Saul king over Israel.
1 Sam 15:10-35 (ESV)
The teaching that the Lord does not change his mind is put in the middle of a story where God changed His course of action. So what is it saying? We know that God was disappointed in Saul and changed his decision on who would be king of Israel because of Saul's great sin, but then we are told that God does not change His mind.
If we put ourselves in the shoes of the Israelites at this time, we can get a better understanding of what is going on. The Israelites were living under a theocracy. God was the one that gave them Saul as king, but then Saul failed to be the holy king that God wanted. Did God make a mistake in appointing Saul? Was God vengeful and appointed a king for Israel that would be evil? Or did Saul not live up to the calling that God had on His life? I would choose the latter in light of the two passages that we have read from Exodus and Jonah.
So the Scripture in 1 Samuel emphasized that God does not change. He has a purpose. He has a will. Those will never change. God is the same yesterday, today, and tomorrow. But his actions can change based upon the faithful living of us. Moses stood up and showed God He could be the leader God wanted, so God changed his mind and relented from punishment. The Ninevites repented and came back to the Lord, so God changed his mind and relented from punishment. God is flexible, changing His course of action on the fly to bring about the greatest outcome. God is not limited, but He has chosen to wait on us to be faithful.
So God never changes in His nature, but He does change in His actions.
God is the God of hope. He hopes for the best. Despite all likeliness to the contrary, He is filled with hope that each one of us will do what is right. That is what stops Him from intervening at times when we deserve punishment; He is hoping for us to change and be the people He can totally use to bring about His will. We must remember that His grace covers our constant failings and mistakes (biblically called sin), and He will use us, if we are willing and sometimes even when we are unwilling, to bring about His will. But He often waits for people to be faithful to transform our neighborhoods, workplaces, and other surroundings into what He has destined it to be.
You may also be interested in God Does Not Know the Future and Change Brings Change but There is an Idea that Keeps Us Chained.